HANA in-memory database main features are: 1. HANA in-memory is a combination of row based, column based and Object-Oriented base technology. 2. It is Hybrid In-memory database; it can store data in row store and column store manner. 3. HANA in-memory use parallel processing with multicore CPU Architecture. 4. HANA In-Memory database takes 5 nanoseconds to reads data whereas other conventional databases take 5 milliseconds to read memory data.
> HANA 2.0 enhance security. Now redo logs and database backup encryption option is available in HANA 2.0 >HANA 1.0 is come out with XSC (extended application service Classic), and HANA 2.0 come out XSA (extend application service Advanced). So, improve application development in XSA. > Enhance Administration tool HANA Cockpit 2.0 introduce in HANA 2.0 > HANA 2.0 Multitenant Database Container while HANA 1.0 is single DB system. > SNAPSHOT Fallback This feature is available in HANA 2.0 SP3. Create a snapshot before any major changes in the database. if something goes wrong then you recover database with this snapshot. Snapshot fallback only work with tenant database. > New Featured in HANA SYSTEM Replication 1. HSR with Active/Active read enable. (Secondary data is available for read only query and use for reporting purpose). 2. Multi target System Replication (enable use to have multiple secondary system instead of a single on. This makes it possible to replicate both inside and outside the datacenter simultaneously.
Delta Merge: Delta merge is a process of moving data from delta area to main area called as delta merges. The purpose of the delta merge operation is to move changes collected in the delta storage to the read-optimized main storage. There are three types of Delta Merge – Hard Merge: Hard merge is a manual execution of merge. Auto Merge: Automatically the data transfer from delta to main by looking ideal time of the system. Smart Merge: It is taken care by system. System takes care to execute at application layer. When you want to execute at application layer it indicates as smart merge. It executed at ABAP application layer.
HANA persists in-memory data by using savepoints. Each HANA service has its own separate savepoints. A savepoint is a periodic point in time, when all the changed data is written to storage, in the form of pages. During a savepoint operation, the HANA database flushes all changed data from memory to the data volumes. The data belonging to a savepoint represents a consistent state of the data on disk and remains so until the next savepoint operation has completed. Redo log entries are written to the log volumes for all changes to persistent data. SQL Query to trigger Save point operation:
ALTER SYSTEM SAVEPOINT
Respective ini parameter is
global.ini ->[persistence]->savepoint_interval_s
The HANA database supports two kinds of license keys: temporary license keys and permanent license keys HANA licenses can be installed for the system database (global) or for a single tenant database (local). Global licenses are for the system database and all the tenant databases, but a license installed in a tenant database governs only that tenant database. If you remove a tenant-specific license key, that tenant database reverts to the global license key installed in the system database
Temporary License Keys: A temporary license key is automatically installed with a new HANA system. A temporary license key is valid for 90 days. During this period, request and install a permanent license key. Permanent License Keys: Types There are two types of permanent license key for HANA: 1.unenforced 2.enforced. >If an unenforced license key is installed, the operation of HANA isn’t affected if its memory consumption exceeds the licensed amount of memory. However, >if an enforced license is installed, the system is locked down when the current memory consumption of HANA exceeds the licensed amount of memory plus some tolerance. If lockdown occurs, either SAP HANA needs to be restarted, or a new license key that covers the amount of memory in use needs to be installed.
You can install permanent license keys in individual tenant databases. The license key installed in a tenant database is valid for that database only and takes precedence over the license key installed in the system database. If a tenant-specific license key isn’t installed, the system database license key is effective in the tenant database. 1. The system view SYS.M_LICENSE provides tenant administrators with information on the license key effective in their tenant database 2. System administrators can use the view SYS_DATABASES.M_LICENSE to see the same information for all tenant databases.
Column tables have several advantages: 1. Higher data compression rates 2. Higher performance for column operations 3. Elimination of additional indexes 4. Elimination of materialized aggregates 5. Parallelization.
